class_docstr: Abstract Filesystem class.
class_docstr_tok: ["Abstract","Filesystem","class","."]
code: def walk(
      top: PathType,
      topdown: bool = True,
      onerror: Optional[Callable[..., None]] = None,
  ) -> Iterable[Tuple[PathType, List[PathType], List[PathType]]]:
      raise NotImplementedError()
  
file_path: tfx/tfx/dsl/io/filesystem.py
imports: from typing import Any, Callable, Iterable, List, Optional, Tuple, Union
label_desc: Use image node_id 13 for calling the Filesystem obj's underlying member method code with example usage: obj.walk(top, topdown, onerror) without return types